Cleanrooms are used, for example, in pharmaceutical and microelectronics manufacturing facilities and in hospitals to provide an atmosphere uncontaminated by dust, pollen, bacteria, molecular pollution, and the like.
Cleanrooms typically comprise a sealed space to which filtered air is supplied by an air circulating system. In order to remove airborne contaminants the air is passed though one or more air filters before it enters the cleanroom. The air then leaves the room through outlet or exhaust filters mounted in a wall near the floor of the room, or in the floor itself.
The inlet air filters are typically mounted filter housings in the ceiling of the cleanroom or in a false ceiling which is suspended from the ceiling of the cleanroom.
The filter housings may for example be arranged in an open gridwork in the ceiling, wherein the grid openings are configured to accommodate the filter housings.
The filter housings are connected through ducts or a plenum to a fan which transports air through the filters into the cleanroom. The air filters are typically panel type HEPA, ULPA or molecular filters comprising substantially rectangular metal, wood or plastic frame in which the filter medium is sealed.
To prevent intrusion of contaminants into the cleanroom, the connection between the air filter and the filter housing must be leak proof so that all outside air and/or recirculated air passes through the filter. A leak proof connection is typically achieved by a flange in the filter housing connecting to a surface on the filter frame, or vice versa. The filter panel is typically secured in a sealing connection with the filter housing using a number of bolts or nuts.
The inlet air filters must be replaced on a regular basis. Changing filters is typically done from the cleanroom side and involves substantial manual work in awkward positions. Cleanrooms can also be very large, which means that the number of filters to be replaced can be substantial. The awkward work of mounting filters in the filter housings also increases the risk of damage to the new filter as it is being mounted.